1. Field of the Invention
This invention relates to an industrial robot, and more particularly, to a guide device for guiding a pipe or a cable connected to an end effector at the tip of a robot wrist.
2. Description of the Prior Art
Generally, in an industrial robot, an end effector suitable for various jobs is mounted to a wrist at the tip of an arm, and a piping member or a wiring member for supply of power and liquid and supply and exhaust of air is connected to the end effector.
FIG. 7 shows the configuration of a six-axis robot as one of industrial robots. The six-axis robot fixed to an installation surface as shown in FIG. 7 is capable of turning by turning axes J1 to J6 at turning angles of xcex8, W, U, xcex3, xcex2 and xcex1. This robot has a wrist 20 at the tip of an arm 10, and an end effector is mounted to the wrist 20.
In the prior art, taps or holes provided in required portions of the robot body for installation of the equipment are used for installation of a cable or like wiring member or a pipe or like piping member connected to the end effector.
FIG. 8A illustrates the installation of the piping member or the wiring member in the prior art. In FIG. 8A, there is shown the state of the piping member or the wiring member attached to the arm and the wrist at the tip of the arm. The wrist 20 has turning axes 21, 22 and 23 connected together, and these turning axes are different from one another in axial direction of turning. An end effector 5 is mounted to one end of the wrist 20 so that it can turn about the turning axis 23 and also can be exchanged. Further, the other end of the wrist 20 is mounted to the arm 10 through the turning axis 21 so that the wrist 20 can turn.
The installation of the piping member or the wiring member is made by means of supporting its intermediate portion with a clamp portion 9 fixed to the arm 10, while holding its end portion in place to a clamp portion 6 fixed to the end effector 5.
According to the installation of the piping member or the wiring member in the prior art, there is a problem in that the wiring member and/or the piping member makes contact with a robot itself or its peripheral equipment to cause wear of the wiring member and/or the piping member, resulting in a need for periodical maintenance.
Generally, when the turning axes of the wrist portion are actuated for wrist motion, the wiring member and/or the piping member moves flexibly with respect to the arm according to the wrist motion. However, in case of a wiring member and/or a piping member of insufficient length, it is not possible to cope with the above flexible motion, resulting in hindrance from carrying out the wrist motion. In this connection, the prior art is configured to meet the flexible motion of the wiring member and/or the piping member by slackening the wiring member and/or the piping member ranging from the arm to the end effector. FIG. 8A shows the installation of the wiring member and/or the piping member slackened.
However, when each turning axis is turned for the wrist motion, the slack of the wiring member and/or the piping member causes contact of the wiring member and/or the piping member with the robot itself or its peripheral equipment. Further, it is feared that the wiring member and/or the piping member gets twisted round the wrist portion to hinder from carrying out the wrist motion, depending on the past motions of the wrist.
Further, the slack of the wiring member and/or the piping member has to be adjusted for each and every robot. Thus, much time is required for the installation of the wiring member and/or the piping member, which is a problem.
FIG. 8B shows how, during one motion, in which turning of the turning axes 21 and 23 causes contact of the slack portion of the wiring member and/or the piping member with the wrist portion, the wiring and/or the piping member can be damaged.
It is an object of the present invention to prevent a wiring member and/or a piping member from interfering with a robot itself or its peripheral equipment.
The present invention relates to a device for guiding a wiring member and/or a piping member connected to an end effector at the tip of a robot wrist via a robot arm. This guide device is adapted to attach a cord-shaped body such as a wiring member and a piping member to a robot, more particularly, to an arm and a wrist portion. The cord-shaped body may include only a wiring member or a piping member, or a bundle of both the wiring member and the piping member, or a body formed by housing the wiring member and the piping member in one pipe. Further, each wiring member or piping member may be configured in a bundle of wiring members or piping members or a body formed by housing the wiring members or the piping members in one pipe, without being limited to a single wiring member or a single piping member.
The guide device for the wiring member and/or the piping member according to the present invention comprises a clamp device having a support portion and a clamp portion capable of loose motion with respect to the support portion and adapted to clamp the wiring member and/or the piping member. In mounting the clamp device to the robot, the support portion is disposed on a robot portion, and the direction of loose motion of the clamp portion is placed to cross the drive axis direction of the robot portion, on which the support portion is disposed.
Arrangement of the guide device of the present invention is determined such that the direction of loose motion of the clamp portion and the drive axis direction of the robot portion, on which the support portion is disposed, may cross each other in mounting the clamp device to the robot portion. With the above configuration, when the wiring member and/or the piping member expand and contract with respect to the arm, the loose motion of the clamp portion occurs. The loose motion of the clamp portion makes it possible to displace the wiring member and/or the piping member according to the wrist motion without making contact with the robot or its peripheral equipment. Thanks to the displacement of the wiring member and/or the piping member, the robot may perform a smooth wrist motion.
The robot portion, on which the support portion is disposed, may be an arm, a turning portion or the like, and the loose motion of the clamp portion may include a translation motion and a turning motion. The guide device of the present invention may take various modes on the basis of the robot portion and the state of loose motion. Incidentally, cross angle between the direction of loose motion of the clamp portion and the drive axis direction of the robot portion can be of any degrees, without being limited to right angle. With this cross angle, force applied to the wiring member and/or the piping member as the result of its flexible motion is decomposed into components in the directions of loose motion of the clamp portion, causing the clamp portion to move loosely. Consequently, the wiring member and/or the piping member is prevented from interfering with the robot or its peripheral equipment.
In the first mode of the present invention, a mounting portion of the clamp device is set on the arm side, a base is adapted for the support portion, and the clamp portion to clamp the wiring member and/or the piping member is configured to be guided in a linear direction with respect to the base and is also capable of turning about an axis perpendicular to the slide direction. Then, the base is disposed on the arm with the slide direction of the clamp portion substantially aligned with the longitudinal direction of the arm.
According to the first mode of the present invention, flexible motion of the wiring member and/or the piping member cause the clamp portion to slide and turn with respect to the arm so that the wiring member and/or the piping member are displaced to a position free from interference with the robot and its peripheral equipment according to the wrist motion. Thus, the wiring member and/or the piping member can be prevented from interfering with the robot and its peripheral equipment, permitting a smooth wrist motion.
In the second mode of the present invention, a mounting portion of the clamp device is set on the arm side, a revolving unit capable of loose motion along the circumference is adapted for the support portion, and the clamp portion to clamp the wiring member and/or the piping member is configured to be capable of turning about an axis which connects the revolving center of the revolving unit and the clamp portion. Then, the clamp portion is placed on the arm with the revolving unit disposed on the circumference of the arm.
According to the second mode of the present invention, flexible motion of the wiring member and/or the piping member cause the clamp portion to revolve and turn with respect to the arm so that the wiring member and/or the piping member are displaced to a position free from interference with the robot and its peripheral equipment according to the wrist motion. Thus, the wiring member and/or the piping member can be prevented from interfering with the robot and its peripheral equipment, permitting a smooth wrist motion.
In the third mode of the present invention, a mounting portion of the clamp device is set on the wrist side, a base is adapted for the support portion, and the clamp portion to clamp the wiring member and/or the piping member is configured to be capable of turning about an axis perpendicular to the installation surface of the base. Then, the clamp portion is placed on the wrist or a wrist casing such that the turning axis of the clamp portion may be aligned with or in parallel to the swing axis of the wrist.
According to the third mode of the present invention, flexible motion of the wiring member and/or the piping member cause the clamp portion to turn with respect to the wrist so that the wiring member and/or the piping member are displaced to a position free from interference with the robot and its peripheral equipment according to the wrist motion. Thus, the piping member and/or the wiring member can be prevented from interfering with the robot and its peripheral equipment, permitting a smooth wrist motion.
In the fourth mode of the present invention, a mounting portion of the clamp device is set on the arm side, a movable unit capable of revolution and sliding along a cylindrical surface is adapted for the support portion, and the clamp portion to clamp the wiring member and/or the piping member is configured to be capable of turning about an axis which connects the revolving center of the movable unit and the clamp portion. Then, the clamp portion is placed on the arm with the movable unit disposed on the circumference of the arm.
According to the fourth mode of the present invention, flexible motion of the wiring member and/or the piping member cause the clamp portion to revolve, slide and turn with respect to the arm so that the wiring member and/or the piping member are displaced to a position free from interference with the robot and its peripheral equipment according to the wrist motion. Thus, the wiring member and/or the piping member can be prevented from interfering with the robot and its peripheral equipment, permitting a smooth wrist motion.
Further, the present invention involves a robot having the above guide device. The robot of the present invention includes a robot comprising the guide device according to at least one of the first to fourth modes described above, or may also include a robot, to which a combination of the above modes or all the above modes are applied.
Incidentally, in the guide device of the present invention, the wiring member and/or the piping member can be attached to the translation axis or the turning axis of the robot without being limited to the arm and the wrist portion.
According to the present invention, the wear caused by contact of the wiring member and/or the piping member with the robot itself and its peripheral equipment can be reduced by preventing the wiring member and/or the piping member from interfering with the robot itself and its peripheral equipment, allowing maintenance operations of the robot and the wiring member and/or the piping member to reduce. Further, the life of the robot and the wiring member and/or the piping member can be extended, permitting less running cost.
Furthermore, the time taken for the installation of the wiring member and/or the piping member can be reduced, permitting less cost required for alteration of a system including the robot.